P
US8166367B2ActiveUtilityPatentIndex 63

Method and apparatus for encoding and decoding channel in a communication system using low-density parity-check codes

Assignee: MYUNG SEHOPriority: Dec 6, 2007Filed: Dec 8, 2008Granted: Apr 24, 2012
Est. expiryDec 6, 2027(~1.4 yrs left)· nominal 20-yr term from priority
Inventors:MYUNG SEHOKWON HWAN-JOONKIM JAE-YOELLIM YEON JUYUN SUNG-RYULLEE HAK-JUJEONG HONG-SILYANG KYEONG-CHEOLJUNG PETERKIM KYUNG-JOONG
H03M 13/2906H03M 13/152H03M 13/618H03M 13/6393H03M 13/1165H03M 13/6362
63
PatentIndex Score
5
Cited by
27
References
20
Claims

Abstract

A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code. The method includes generating a plurality of column groups by grouping (categorizing) columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; determining a range of an information word desired to be obtained by performing shortening; based on the determined range of the information word, performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern; and LDPC encoding the shortened information word.

Claims

exact text as granted — not AI-modified
1. A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the method comprising:
 (a) generating a plurality of column groups by categorizing columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; 
 (b) determining a range of the information word desired to be obtained by performing shortening; 
 (c) based on the determined range of the information word, performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern; and 
 (d) LDPC encoding the shortened information word. 
 
     
     
       2. The method of  claim 1 , wherein performing column group-by-column group shortening in (c) comprises:
 (e) shortening all column groups in order according to the predetermined shortening pattern, and when a part of a particular column group is shortened, shortening no columns in positions corresponding to 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits. 
 
     
     
       3. The method of  claim 1 , wherein performing column group-by-column group shortening in (c) comprises:
 applying a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code is 16200 and a length of an information word is 3240; 
 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups  
                 
                     
                   corresponding to π(0) th , π(1) th , . . . , and  
                 
                     
                   π(m-1) th  column groups, and additionally  
                 
                     
                   shortens 3240-K 2 -360 m information bits  
                 
                     
                   from a π(m) th  column group. Herein, π  
                 
                     
                   denotes a permutation function meaning a  
                 
                     
                   shortening pattern, and a relationship  
                 
                     
                   therebetween is shown at the bottom of the  
                 
                     
                   table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns in  
                 
                     
                   the positions corresponding to the 168  
                 
                     
                   BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(6) th    
                 
                     
                   column groups, and shortens all columns  
                 
                     
                   except for the columns in the positions  
                 
                     
                   corresponding to 168 BCH parity bits from  
                 
                     
                   the π(7) = 8 th  column group. Further,  
                 
                     
                   additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(8) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes the number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       4. The method of  claim 1 , wherein performing column group-by-column group shortening comprises:
 applying a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code is 16200 and a length of an information word is 7200; 
 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups  
                 
                     
                   corresponding to π(0) th , π(1) th , . . . , and  
                 
                     
                   π(m-1) th  column groups, and additionally  
                 
                     
                   shortens 7200-K 2 -360 m information bits  
                 
                     
                   from a π(m) th  column group. Herein, π  
                 
                     
                   denotes a permutation function meaning a  
                 
                     
                   shortening pattern, and a relationship  
                 
                     
                   therebetween is shown at the bottom of the  
                 
                     
                   table.  
                 
                     
                   However, when a part of a π(18) = 19 th    
                 
                     
                   column group is shortened, the columns in  
                 
                     
                   the positions corresponding to the 168  
                 
                     
                   BCH parity bits are not subjected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(17) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH parity  
                 
                     
                   bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2    
                 
                     
                   information bits from a π(19) = 0 th  column  
                 
                     
                   group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       5. A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the method comprising:
 (a) generating a plurality of column groups by categorizing columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; 
 (b) determining a range of the information word desired to be obtained by performing shortening; 
 (c) based on the determined range of the information word, performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern; and 
 (d) LDPC encoding the shortened information word; 
 wherein performing column group-by-column group shortening comprises including 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits in an information word desired to be obtained by performing shortening, and shortening columns except for columns in positions corresponding to the 168 BCH parity bits. 
 
     
     
       6. The method of  claim 5 , wherein performing column group-by-column group shortening in (c) comprises:
 applying a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code comprises 16200 and a length of an information word comprises 3240; 
 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column  
                 
                     
                   groups, and additionally shortens 3240- 
                 
                     
                   K 2 -360 m information bits from a π(m) th    
                 
                     
                   column group. Herein, π denotes a  
                 
                     
                   permutation function meaning a  
                 
                     
                   shortening pattern, and a relationship  
                 
                     
                   therebetween is shown at the bottom of  
                 
                     
                   the table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns  
                 
                     
                   in the positions corresponding to the 168  
                 
                     
                   BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(6) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(7) = 8 th  column  
                 
                     
                   group. Further, additionally shortens 528- 
                 
                     
                   K 2  information bits from a π(8) = 0 th    
                 
                     
                   column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying a following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       7. The method of  claim 5 , wherein performing column group-by-column group shortening in (c) comprises:
 applying a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code comprises 16200 and a length of an information word comprises 7200; 
 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column groups, and  
                 
                     
                   additionally shortens 7200-K 2 -360 m information 
                 
                     
                   bits from a π(m) th  column group. Herein, π denotes a 
                 
                     
                   permutation function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is shown at the  
                 
                     
                   bottom of the table. 
                 
                     
                   However, when a part of a π(18) = 19 th  column  
                 
                     
                   group is shortened, the columns in the positions  
                 
                     
                   corresponding to the 168 BCH parity bits are not  
                 
                     
                   subjected to shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(17) th  column  
                 
                     
                   groups, and shortens all columns except for the  
                 
                     
                   columns in the positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(19) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying a following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       8. An apparatus for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:
 a parity-check matrix extractor for generating a plurality of column groups by grouping columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; 
 a shortening pattern applier for determining a range of an information word desired to be obtained by performing shortening, and based on a determined range of the information word, for performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern; and 
 an encoder for LDPC encoding the shortened information word. 
 
     
     
       9. The apparatus of  claim 8 , wherein in performing column group-by-column group shortening, the shortening pattern applier shortens all column groups in order according to the predetermined shortening pattern, and when a part of a column group is shortened, shortens no columns in positions corresponding to 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits. 
     
     
       10. The apparatus of  claim 8 , wherein in performing column group-by-column group shortening, the shortening pattern applier applies a shortening pattern defined in the following table when applying shortening to an LDPC code for which a length of an LDPC code is 16200 and a length of an information word comprises 3240; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Range of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column  
                 
                     
                   groups, and additionally shortens 3240- 
                 
                     
                   K 2 -360 m information bits from a π(m) th    
                 
                     
                   column group. Herein, π denotes a  
                 
                     
                   permutation function meaning a shorten- 
                 
                     
                   ing pattern, and a relationship  
                 
                     
                   therebetween is shown at the bottom of  
                 
                     
                   the table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns  
                 
                     
                   in the positions corresponding to the 168  
                 
                     
                   BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(6) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(7) = 8 th  column  
                 
                     
                   group. Further, additionally shortens 528- 
                 
                     
                   K 2  information bits from a π(8) = 0 th    
                 
                     
                   column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  is an integer. 
     
     
       11. The apparatus of  claim 8 , wherein in performing column group-by-column group shortening, the shortening pattern applier applies a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code comprises 16200 and a length of an information word comprises 7200; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column groups, and  
                 
                     
                   additionally shortens 7200-K 2 -360 m information 
                 
                     
                   bits from a π(m) th  column group. Herein, π denotes a 
                 
                     
                   permutation function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is shown at the  
                 
                     
                   bottom of the table. 
                 
                     
                   However, when a part of a π(18) = 19 th  column  
                 
                     
                   group is shortened, the columns in the positions  
                 
                     
                   corresponding to the 168 BCH parity bits are not  
                 
                     
                   subjected to shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(17) th  column  
                 
                     
                   groups, and shortens all columns except for the  
                 
                     
                   columns in the positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(19) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       12. An apparatus for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:
 a parity-check matrix extractor for generating a plurality of column groups by grouping columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; 
 a shortening pattern applier for determining a range of an information word desired to be obtained by performing shortening, and based on the determined range of the information word, for performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern; and 
 an encoder for LDPC encoding the shortened information word; 
 wherein in performing column group-by-column group shortening, the shortening pattern applier includes 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits in an information word desired to be obtained by performing shortening, and shortens columns except for columns in positions corresponding to the 168 BCH parity bits. 
 
     
     
       13. The apparatus of  claim 12 , wherein in performing column group-by-column group shortening, the shortening pattern applier applies a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code is 16200 and a length of an information word is 3240; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m groups corresponding  
                 
                     
                   to π(0) th , π(1) th , . . . , and π(m-1) th    
                 
                     
                   column groups, and additionally  
                 
                     
                   shortens 3240-K 2 -360 m information  
                 
                     
                   bits from a π(m) th  column group.  
                 
                     
                   Herein, π denotes a permutation  
                 
                     
                   function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is  
                 
                     
                   shown at the bottom of the table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns  
                 
                     
                   in the positions corresponding to the  
                 
                     
                   168 BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(6) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(7) = 8 th  column  
                 
                     
                   group. Further, additionally shortens  
                 
                     
                   528-K 2  information bits from a π(8) =  
                 
                     
                   0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  is an integer. 
     
     
       14. The apparatus of  claim 12 , wherein in performing column group-by-column group shortening, the shortening pattern applier applies a shortening pattern defined in a following table when applying shortening to an LDPC code for which a length of an LDPC code comprises 16200 and a length of an information word comprises 7200; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column groups, and  
                 
                     
                   additionally shortens 7200-K 2 -360 m information 
                 
                     
                   bits from a π(m) th  column group. Herein, π denotes a 
                 
                     
                   permutation function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is shown at the  
                 
                     
                   bottom of the table. 
                 
                     
                   However, when a part of a π(18) = 19 th  column  
                 
                     
                   group is shortened, the columns in the positions  
                 
                     
                   corresponding to the 168 BCH parity bits are not  
                 
                     
                   subjected to shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(17) th  column  
                 
                     
                   groups, and shortens all columns except for the  
                 
                     
                   columns in the positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(19) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       15. A method for decoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the method comprising:
 (a) demodulating a signal transmitted from a transmitter; 
 (b) determining a position of a shortened bit by estimating information on a shortening pattern of an LDPC code from the demodulated signal from (a); and 
 (c) decoding data using the determined position of the shortened bit. 
 
     
     
       16. The method of  claim 15 , wherein the information on a shortening pattern comprises a shortening pattern defined in a following table; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m groups corresponding  
                 
                     
                   to π(0) th , π(1) th , . . . , and π(m-1) th    
                 
                     
                   column groups, and additionally  
                 
                     
                   shortens 3240-K 2 -360 m information  
                 
                     
                   bits from a π(m) th  column group.  
                 
                     
                   Herein, π denotes a permutation  
                 
                     
                   function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is  
                 
                     
                   shown at the bottom of the table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns  
                 
                     
                   in the positions corresponding to the  
                 
                     
                   168 BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(6) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(7) = 8 th  column  
                 
                     
                   group. Further, additionally shortens  
                 
                     
                   528-K 2  information bits from a π(8) =  
                 
                     
                   0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       17. The method of  claim 15 , wherein the information on a shortening pattern comprises a shortening pattern defined in a following table; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column groups, and  
                 
                     
                   additionally shortens 7200-K 2 -360 m information 
                 
                     
                   bits from a π(m) th  column group. Herein, π denotes a 
                 
                     
                   permutation function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is shown at the  
                 
                     
                   bottom of the table. 
                 
                     
                   However, when a part of a π(18) = 19 th  column  
                 
                     
                   group is shortened, the columns in the positions  
                 
                     
                   corresponding to the 168 BCH parity bits are not  
                 
                     
                   subjected to shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(17) th  column  
                 
                     
                   groups, and shortens all columns except for the  
                 
                     
                   columns in the positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(19) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       18. An apparatus for decoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:
 a demodulator for demodulating a signal transmitted from a transmitter; 
 a shortening pattern determiner for determining a position of a shortened bit by estimating information on a shortening pattern of an LDPC code from the demodulated signal; and 
 a decoder for decoding data using the determined position of the shortened bit. 
 
     
     
       19. The apparatus of  claim 18 , wherein the information on a shortening pattern comprises a shortening pattern defined in a following table; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 3240, M 1  = 360, q = 36 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 3240 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   3240 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m groups corresponding  
                 
                     
                   to π(0) th , π(1) th , . . . , and π(m-1) th    
                 
                     
                   column groups, and additionally  
                 
                     
                   shortens 3240-K 2 -360 m information  
                 
                     
                   bits from a π(m) th  column group.  
                 
                     
                   Herein, π denotes a permutation  
                 
                     
                   function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is  
                 
                     
                   shown at the bottom of the table. 
                 
                     
                   However, when a part of a π(7) = 8 th    
                 
                     
                   column group is shortened, the columns  
                 
                     
                   in the positions corresponding to the  
                 
                     
                   168 BCH parity bits are not subected to  
                 
                     
                   shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and  
                 
                     
                   π(6) th  column groups, and shortens all  
                 
                     
                   columns except for the columns in the  
                 
                     
                   positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(7) = 8 th  column  
                 
                     
                   group. Further, additionally shortens  
                 
                     
                   528-K 2  information bits from a π(8) =  
                 
                     
                   0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                 
                     
                 
                   7 
                   3 
                   6 
                   5 
                   2 
                   4 
                   1 
                   8 
                   0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer. 
     
     
       20. The apparatus of  claim 18 , wherein the information on a shortening pattern comprises a shortening pattern defined in a following table; 
       
         
           
                 
                 
               
                     
                 
                   Major variables of  
                   N 1  = 16200, K 1  = 7200, M 1  = 360, q = 25 
                 
                   DVB-S2 LDPC  
                     
                 
                   code 
                     
                 
                   Scope of K 2   
                   Shortening Method 
                 
                     
                 
                   1) 528 ≦ K 2  < 7200 
                   
                     
                       
                         
                           
                             
                               For 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               an 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               integer 
                               ⁢ 
                               
                                   
                               
                               ⁢ 
                               m 
                             
                             = 
                             
                               ⌊ 
                               
                                 
                                   7200 
                                   - 
                                   
                                     K 
                                     2 
                                   
                                 
                                 360 
                               
                               ⌋ 
                             
                           
                           , 
                         
                       
                     
                   
                 
                     
                   shortens all of m column groups corresponding to  
                 
                     
                   π(0) th , π(1) th , . . . , and π(m-1) th  column groups, and  
                 
                     
                   additionally shortens 7200-K 2 -360 m information 
                 
                     
                   bits from a π(m) th  column group. Herein, π denotes a 
                 
                     
                   permutation function meaning a shortening pattern,  
                 
                     
                   and a relationship therebetween is shown at the  
                 
                     
                   bottom of the table. 
                 
                     
                   However, when a part of a π(18) = 19 th  column  
                 
                     
                   group is shortened, the columns in the positions  
                 
                     
                   corresponding to the168 BCH parity bits are not  
                 
                     
                   subjected to shortening. 
                 
                   2) 168 ≦ K 2  < 528 
                   Shortens all of π(0) th , π(1) th , . . . , and π(17) th  column  
                 
                     
                   groups, and shortens all columns except for the  
                 
                     
                   columns in the positions corresponding to 168 BCH  
                 
                     
                   parity bits from the π(18) = 19 th  column group.  
                 
                     
                   Further, additionally shortens 528-K 2  information  
                 
                     
                   bits from a π(19) = 0 th  column group. 
                 
                     
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
                 
               
                   π(0) 
                   π(1) 
                   π(2) 
                   π(3) 
                   π(4) 
                   π(5) 
                   π(6) 
                   π(7) 
                   π(8) 
                   π(9) 
                 
                     
                 
                   18 
                   17 
                   16 
                   15 
                   14 
                   13 
                   12 
                   11 
                    4 
                   10 
                 
                     
                 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                   π 
                 
                   (10) 
                   (11) 
                   (12) 
                   (13) 
                   (14) 
                   (15) 
                   (16) 
                   (17) 
                   (18) 
                   (19) 
                 
                     
                 
                    9 
                    8 
                    3 
                    2 
                    7 
                    6 
                    5 
                    1 
                   19 
                    0 
                 
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
             
                
                
                
                
                
                
                
                
                
               
            
           
         
         where N 1  denotes a length of an LDPC code, K 1  denotes a length of an information word, M 1  denotes a number of columns constituting one column group, and q is an integer satisfying the following equation:
     q= ( N   1   −K   1 )/ M   1    
 
       
       where K 1 /M 1  comprises an integer.

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